TORONTO -- The Special Investigations Unit (SIU) is investigating after a 13-year-old boy allegedly crashed a vehicle into a fuel truck and a transit bus in North York early Tuesday morning, leaving another 13-year-old boy suffering from “life-altering injuries”.

The SIU said a police officer spotted the two 13-year-olds travelling in a SUV, which belonged to a family member of the injured boy, near Dufferin and Centre streets in Vaughan around 4:40 a.m.

As the officer attempted to stop the SUV, the driver fled from the scene.

The SUV then travelled south to the intersection of Finch Avenue West and Dufferin Street where it struck a fuel truck at a high-rate of speed, police said.

A GO Transit bus was also struck after the initial collision, but was was not carrying any passengers at the time.

The alleged 13-year-old driver of the SUV was taken into police custody at the scene.

The 13-year-old passenger of the SUV was rushed to hospital with a serious leg injury, police said.

"I believe right now he is currently in surgery at the hospital. By the level of injury I have heard, it is going to be a serious, life-altering injury that he has sustained," Sgt. Murray Campbell told reporters at the scene.

Meanwhile, a man, who identified himself as the father of the injured boy, told reporters at the scene of the crash that the damaged SUV belongs to him.

The father said he last saw his son around 12 a.m. in their home, located in the Jane Street and Finch Avenue area, but then went to sleep.

"The next thing I know the hospital is calling saying he is in emergency," the man said.

The father also said he doesn’t know the 13-year-old boy who was driving his vehicle.

No other injuries were reported in the incident.

The intersection has since reopened.

The SIU is an arm's length agency called in to investigate whenever police are involved in an incident that results in a death, serious injury or allegations of sexual assault.